Page 1 of 10 Body Area Networks (BAN) Erik Karulf, [email protected] (A survey paper written under guidance of Prof. Raj Jain) Download Abstract A Body Area Network is formally defined by IEEE 802.15 as, "a communication standard optimized for low power devices and operation on, in or around the human body (but not limited to humans) to serve a variety of applications including medical, consumer electronics / personal entertainment and other" [IEEE 802.15]. In more common terms, a Body Area Network is a system of devices in close proximity to a persons body that cooperate for the benefit of the user. This paper discusses several uses of the BAN technology As IEEE mentioned, the most obvious application of a BAN is in the medical sector, however there are also more recreational uses to BANs. This paper will discuss the technologies surrounding BANs, as well as several common applications for BANs. At the end of the paper we will briefly discuss the challenges associated with BANs and some solutions that are on the horizon. Keywords: Body Area Networks, Body Sensor Networks, Sensor Networks, Personal Area Networks, Healthcare Applications, IEEE 802.15 Table of Contents • 1. Introduction to Body Area Network Technology • 2. History and Development of BAN • 3. Applications in Healthcare o 3.1 Managed Sensor Networks o 3.2 Autonomous Sensor Networks o 3.3 Case Study: Cardiac Monitoring • 4. Challenges associated with BAN o 4.1 Signal & Path Performance o 4.2 Usability • 5. Summary • A. References • B. List of AcronymsPage 2 of 10 1. Introduction The field of computer science is constantly evolving to process larger data sets and maintain higher levels of connectivity. At same time, advances in miniaturization allow for increased mobility and accessibility. Body Area Networks represent the natural union between connectivity and miniaturization. A Body Area Network (BAN) is defined formally as a system of devices in close proximity to a persons body that cooperate for the benefit of the user. The BBC's Jo Twist gave a more informal definition of Body Area Networks in her article title When technology gets personal: Inanimate objects will start to interact with us: we will be surrounded - on streets, in homes, in appliances, on our bodies and possibly in our heads - by things that "think". Forget local area networks - these will be body area networks. [Twist04] Twist makes the possibility of BAN sound more like science fiction than a real possibility, but several experts in the field expect to see BAN in production for general use by 2010 [Schmidt02]. While this might seem like an aggressive estimate, when put into context with the history and development of BAN up to this point it becomes a much more achievable goal. In the paper we will start off introducing the reader to the history and development of BAN. We will cover the medical heritage of BAN and how the technology grew from a simple generalization of the concept of Body Sensor Networks (BSN). We will investigate current applications of BAN with an emphasis on applications in the medical sector. As we cover applications of BAN, we will spend a portion of the paper identifying some of technical problems facing BAN. Finally, we will conclude the paper with several solutions currently in development and how they hope to address and overcome the challenges inherent to BAN. Back to Table of Contents 2. History and Development of BAN BAN technology is still an emerging technology, and as such it has a very short history. BAN technology emerges as the natural byproduct of existing sensor network technology and biomedical engineering. Professor Guang-Zhong Yang was the first person to formally define the phrase "Body Sensor Network" (BSN) with publication of his book Body Sensor Networks in 2006. BSN technology represents the lower bound of power and bandwidth from the BAN use case scenarios. However, BAN technology is quite flexible and there are many potential uses for BAN technology in addition to BSNs. Some of the more common use cases for BAN technology are:Page 3 of 10 • Body Sensor Networks (BSN) • Sports and Fitness Monitoring • Wireless Audio • Mobile Device Integration • Personal Video Devices Each of these use cases have unique requirements in terms of bandwidth, latency, power usage, and signal distance. IEEE 802.15 is the working group for Wireless Personal Area Networks (WPAN) [IEEE 802.15]. The WPAN working group realized the need for a standard for use with devices inside and around close proximity to the human body. IEEE 802.15 established Task Group #6 to develop the standards for BAN. The BAN task group has drafted a (private) standard that encompasses a large range of possible devices. In this way, the task group has given application and device developers the decision of how to balance data rate and power. Figure 1, below, describes the ideal position for BAN in the power vs data rate spectrum. Figure 1 - Data Rate vs Power [IEEE-BAN-SUMMARY] As you can see the range of BAN devices can vary greatly in terms of bandwidth and power consumption. The BAN draft requirements, displayed below, add a common set of requirements as to ensure that all devices conform to a similar set of behaviors yet still encompass a wide variety of devices as previously mentioned.Page 4 of 10 Table 1 - BAN Draft Specifications [IEEE-BAN-SUMMARY] Distance 2 m standard 5 m special use Network Density 2 - 4 nets / m2 Network Size Max: 100 devices / network Power Consumption ~1 mW / Mbps Startup Time < 100 us or < 10% of Tx slot Latency (end to end) 10 ms Network setup time < 1 sec (Per device setup time excludes network initialization) Effective sleep modes Operation in global, license-exempt band Effective sleep modes Peer to Peer, and Point to Multi-point communication Future proof Upgradeable, scaleable, backwards compatible Quality of Service & Guaranteed Bandwidth Concurrent availability of asynchronous and isochronous channels Very Low, Low, and High duty cycle modes Allows device driven degradation of services Back to Table of Contents 3. Applications in Healthcare As previously mentioned, BANs have grown as a refinement of BSN. As such, BSN remain the most thought out applications of BAN. In his summary of the BAN task group's findings thus far, Stefan Drude, a researcher at Phillips, outlined the possible needs the group had found for the very
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